"Normally, the warm air is at the surface and it's colder as you go up," said Jeff Weber with University Corporation for Atmospheric Research.

For this reason, the air at ground level is a lot more dense, which is a perfect condition for sound to travel. That means we can hear things more crisply like Sunday's flyover, according to Weber.

"When we have these sharp differences in temperature, we call it a steep gradient," he said. "It creates kind of like an artificial surface, almost like a boundary. So, it actually is a physical difference in densities between these two air parcels. That difference in density acts as a lens, or a lid, on top of that and bounces it back down to the observer on the ground."

Weber said sound tries to escape into the upper atmosphere, but because of that difference in densities, it instead bends back down through the cold air.

Sound also persists a little longer in more dense air because it moves slower than it does in warm air.